public class Example4_20 { 
  public static void main(String args[ ]) { 
    char a[]={'a','b','c','D','E','F'};
    for(int i=0;i<a.length;i++) { 
      if(Character.isLowerCase(a[i]))    
        a[i]=Character.toUpperCase(a[i]);
      else if(Character.isUpperCase(a[i]))
        a[i]=Character.toLowerCase(a[i]);
  }
    for(int i=0;i<a.length;i++)   
      System.out.print(" "+a[i]);
   } 
}

